In recent years, organic EL display devices have received attention as a next-generation flat panel display device. The organic EL display device emits light by itself, and has excellent viewing angle characteristics, high visibility, low power consumption, and a small thickness. Therefore, there is an increasing demand for the organic EL display device.
The organic EL display device includes a plurality of organic EL elements arranged in a predetermined pattern. Each organic EL element includes a first electrode (anode) formed on an insulating substrate, an organic layer having a light emitting layer formed on the first electrode, and a second electrode (cathode) formed on the organic layer.
Here, the organic layer can be damaged by water, and therefore, needs to be shut off from water contained in ambient air. Therefore, conventionally, a technique has been proposed in which the organic layer is sealed between the first substrate on which the organic layer is formed and the second substrate facing the first substrate so that the organic layer is shut off from water. More specifically, an organic EL display device has been proposed in which the first and second substrates are bonded together using a resinous adhesive material to seal the organic layer.
However, in this organic EL display device, the adhesive material is made of a resin and therefore transmits water contained in ambient air, and therefore, it is difficult to completely shut out water. The adhesive material made of a resin transmits oxygen contained in ambient air as well. Therefore, the second electrode formed on the organic layer is oxidized, so that the performance of the second electrode is disadvantageously lowered.
Therefore, an organic EL display device has been proposed which employs a sealing member made of fritted glass (low-melting-point glass) instead of the adhesive material made of a resin. If the sealing member made of fritted glass is used to seal the organic layer, the organic layer can be shut off from water and oxygen better than when the adhesive material made of a resin is used, so that the sealing performance of the sealing member is improved.
However, the sealing member is formed along the circumference of the organic layer, and therefore, a space is formed inside the sealing member (i.e., between the organic layer formed on the first substrate, and the second substrate). Therefore, in particular, in the case of a large-size organic EL display device employing glass substrates as the first and second substrates, the glass substrates are warped in the space by their own heavy weight, so that the first and second substrates contact each other, and therefore, the mechanical strength of the organic EL display device is disadvantageously lowered.
Therefore, a technique has been described to improve the mechanical strength of the organic EL display device employing a sealing member made of fitted glass. More specifically, a resin member made of a urethane acrylic resin is provided in the space formed between the organic layer formed on the first substrate, and the second substrate. The resin member is formed in the following manner: the urethane acrylic resin is injected inside the sealing member made of fritted glass formed along the circumference of the organic layer, and thereafter, the urethane acrylic resin is cured by irradiation with light or heating, thereby forming a film-like resin member (see, for example, PATENT DOCUMENT 1).